Sit-up exercise device



FIG. 1 is a top plan view of a sit-up exercise device showing my newdesign;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a side elevational view thereof, the side opposite beingsubstantially a mirror image.

The ornamental design for a sit-up exercise device, substantially asshown and described.